package org.cn.zhaozhx.util;

import java.io.FileInputStream;
import java.io.InputStream;
import java.security.MessageDigest;

/**
 * @ClassName: org.cn.zhaozhx.util.HashFile
 * @Description: 校验文件的MD5\SHA1...
 */
public class HashFile {
    public static char[] hexChar = { '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'a', 'b', 'c', 'd', 'e', 'f' };
    
    /**
     * @Description: 获取文件的MD5\SHA1...
     * @param fileName
     * @param hashType
     * @return
     * @throws Exception
     */
    public static String getHash(String fileName, String hashType) throws Exception {
        InputStream fis;
        fis = new FileInputStream(fileName);
        byte[] buffer = new byte[1024];
        MessageDigest md5 = MessageDigest.getInstance(hashType);
        int numRead = 0;
        while ((numRead = fis.read(buffer)) > 0) {
            md5.update(buffer, 0, numRead);
        }
        fis.close();
        return toHexString(md5.digest());
    }
    
    private static String toHexString(byte[] b) {
        StringBuilder sb = new StringBuilder(b.length * 2);
        for (int i = 0; i < b.length; i++) {
            sb.append(hexChar[(b[i] & 0xf0) >>> 4]);
            sb.append(hexChar[b[i] & 0x0f]);
        }
        return sb.toString();
    }
    
    public static void main(String[] args) throws Exception {
        String fileName = "d:\\temp\\Windows8-ConsumerPreview-32bit-ChineseSimplified.iso";
        String hashType = "MD5";
        System.out.println(hashType + " == " + getHash(fileName, hashType));
        hashType = "SHA1";
        System.out.println(hashType + " == " + getHash(fileName, hashType));
        hashType = "SHA-256";
        System.out.println(hashType + " == " + getHash(fileName, hashType));
        hashType = "SHA-384";
        System.out.println(hashType + " == " + getHash(fileName, hashType));
        hashType = "SHA-512";
        System.out.println(hashType + " == " + getHash(fileName, hashType));
        
    }
}
